Attenuation correction for nuclear medical imaging scanners with simultaneous transmission and emission acquisition

A method of nuclear medical imaging wherein gamma events are detected by gamma detectors of a scanner, said method comprising:

• acquiring blank transmission data of gamma events detected by the gamma detectors when a patient is absent from the scanner, and simultaneously acquiring patient emission data and patient transmission data of gamma events detected by the gamma detectors, the patient emission data resulting from radioisotope in a patient, and the patient transmission data resulting from radiation from a transmission source external to the patient including radiation passing through the patient;
• adjusting the blank scan data according to count rate at which the patient emission data are obtained from the gamma detectors;
• using the adjusted blank scan data and the patient transmission data for attenuation correction of the patient emission data;
• and
• using the attenuation corrected patient emission data for producing a tomographic image from the patient.

A nuclear medical imaging system comprising:

• a scanner including gamma detectors mounted for being circumferentially disposed about a patient, and a transmission source mounted for transmission scanning of the patient, and
• at least one data processor coupled to the gamma detectors and programmed for simultaneously acquiring patient emission data and patient transmission data of gamma events detected by the gamma detectors, the patient emission data resulting from radioisotope in the patient, and the patient transmission data resulting from radiation from the transmission source including radiation passing through the patient,
• wherein said at least one data processor is also programmed for using the patient transmission data for attenuation correction of the patient emission data, and using the attenuation corrected patient emission data for producing a tomographic image from the patient,
• wherein said at least one data processor is further programmed for correcting for spatially varying count rate effects on the attenuation correction,
• wherein said at least one processor is programmed for acquiring blank transmission data from the gamma detectors when the patient is absent from the scanner, and using the blank transmission data for the attenuation correction of the patient emission data, and
• wherein said at least one processor is programmed for correcting for spatially varying count rate effects on the attenuation correction by adjusting the blank scan data according to a count rate at which the patient emission data are obtained from the gamma detectors.

A system for nuclear medical imaging comprising:

• a scanner including gamma detectors mounted for being circumferentially disposed about a patient, and a transmission source mounted for transmission scanning of the patient;
• and
• at least one data processor coupled to the gamma detectors and programmed for
• acquiring blank transmission data of gamma events detected by the gamma detectors when a patient is absent from the scanner, and simultaneously acquiring patient emission data and patient transmission data of gamma events detected by the gamma detectors, the patient emission data resulting from radioisotope in a patient, and the patient transmission data resulting from radiation from a transmission source external to the patient including radiation passing through the patient,
• adjusting the blank scan data according to a count rate at which the patient emission data are obtained from the gamma detectors,
• using the adjusted blank scan data and the patient transmission data for attenuation correction of the patient emission data, and
• using the attenuation corrected patient emission data for producing a tomographic image from the patient.